2.4 A tank is partially filled with 100 gallons of fluid in which 10 pounds of salt is dissolved. Suppose that brine containing 1 pound of salt per gallon is pumped into the tank at a rate of 3 gallons per minute. Well mixed solution is then pumped out of the tank. (a) Suppose that the well-mixed solution flows out of the tank at 3 gallons per minute. Find the concentration of salt in the tank at time t. (b) Suppose that the well-mixed solution flows out of the tank at 4 gallons per minute. Find the concentration of salt in the tank when there are 50 gallons of fluid in the tank